We propose to focus on psychological development during the onset of aging, i.e., from the mid 50s to ages 65-68. Our objective is to delineate psychological aging as a multidimensional, nonlinear, and dynamic process in the context of changing life circumstances and social relationships. We will examine how maturational changes influence psychological trajectories, and how specific contexts of aging interact with developmental change. We focus primarily on three sets of psychological factors: personality, psychological well-being (PWB), and psychological distress (e.g., depressive symptoms, anxiety, anger, and alcohol use). There is both a theoretical and practical rationale for documenting the relationships of social situations and activities with psychological change among older adults;such knowledge may suggest potential lines of intervention to improve quality of life and reduce dependency. Our analyses will be based primarily on a large, longitudinal social survey, the Wisconsin Longitudinal Study (WLS). The existing WLS data, collected from 1957 through 2007, provide measures of the above-mentioned psychological variables at two time points (ages 53-54 and 65-66). The availability of the WLS sibling data multiple times and ages of measurement will allow us to develop models that account for measurement errors and for unobserved individual heterogeneity. Our specific aims are: 1. To assess the structure and temporal stability of personality and psychological well-being (PWB) in the WLS and two other large, nationally representative studies, Midlife in the United States (MIDUS) and the National Survey of Families and Households (NSFH). 2. To estimate reciprocal relationships among psychological characteristics (personality, PWB, and distress) and the social roles and activities of older adults (including work conditions, social participation, leisure activities, and the exchange of social support). 3. To examine the reciprocal relationships between personality change and changes in health, marital status, and employment. 4. To validate hypothesized relationships between selected genetic markers (5-HTTLPR, 5HTR1A, 5HTR2A, 5HTR2C, MAOA, TPH, DRD2, DRD4) and indicators of psychological distress (i.e., depressive symptoms, alcohol use, hostility, and anxiety). 5. To track both short-term and enduring effects of changing family roles and other life transitions on psychological well-being and psychological distress. 6. To assess prospectively whether the effects of family roles and transitions on psychological outcomes are moderated by genetic makeup;this analysis will draw on newly collected DMA data, including indicators of several variable number tandem repeats (VNTRs) that are related to psychological outcomes (e.g., 5-HTTLPR, DRD4).